Patent application title: Stable laquinimod preparations

Abstract:

The subject invention provides a pharmaceutical composition comprising
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide or the salt thereof; a pharmaceutically acceptable carrier;
and not more than 0.5% w/w relative to
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide of
2-Chloro-6-(1-ethyl-N-methyl-2-oxoindoline-3-carboxamido)benzoic
acid,1H,3H-spiro[5-chloro-1-methylquinoline-2,4-dione-3,3'-[1]ethylindoli-
n-[2]-one], or
5-Chloro-N-ethyl-3-hydroxy-1-methyl-2,4-dioxo-N-phenyl-1,2,3,4-tetrahydro-
-quinoline-3-carboxamide.

2. The pharmaceutical composition of claim 1, wherein the
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide is in the form of a pharmaceutically acceptable salt.

3. The pharmaceutical composition of claim 2, wherein the pharmaceutically
acceptable salt of
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide is a lithium salt, a sodium salt or a calcium salt.

6. The pharmaceutical composition of claim 1 characterized in that 1.0% or
less of the of
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide or of the pharmaceutically acceptable salt thereof degrades
upon exposure to a 0.15% H2O2 solution for 40 minutes.

7. The pharmaceutical composition according to claim 1, wherein the
pharmaceutical composition is free of oxidation decomposition products of
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide.

8. The pharmaceutical composition of according to claim 1, wherein the
pharmaceutical composition contains an undetectable amount of oxidation
decomposition products of
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide.

9. The pharmaceutical composition of according to claim 1, wherein the
pharmaceutical composition contains less than 1% by weight of oxidation
decomposition products of
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide.

10. The pharmaceutical composition of claim 7, wherein the pharmaceutical
composition is free of
2-Chloro-6-(1-ethyl-N-methyl-2-oxoindoline-3-carboxamido)benzoic
acid,1H,3H-spiro[5-chloro-1-methylquinoline-2,4-dione-3,3'-[1]-ethylindol-
in-[2]-one], and
5-Chloro-N-ethyl-3-hydroxy-1-methyl-2,4-dioxo-N-phenyl-1,2,3,4-tetrahydro-
-quinoline-3-carboxamide.

11. The pharmaceutical composition of claim 1 which contains not more than
0.5% w/w relative to
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide of
2-Chloro-6-(1-ethyl-N-methyl-2-oxoindoline-3-carboxamido)benzoic
acid,1H,3H-spiro[5-chloro-1-methylquinoline-2,4-dione-3,3'-[1]ethylindoli-
n-[2]-one], or
5-Chloro-N-ethyl-3-hydroxy-1-methyl-2,4-dioxo-N-phenyl-1,2,3,4-tetrahydro-
-quinoline-3-carboxamide.

12-14. (canceled)

15. A pharmaceutical formulation in tablet form wherein the tablet
comprises a core comprising
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide or a pharmaceutically acceptable salt thereof and a
pharmaceutically acceptable carrier and a coating which inhibits oxygen
from contacting the core.

16. The pharmaceutical formulation of claim 15, wherein the coating
comprises a cellulosic polymer, a detackifier, a gloss enhancer, and
pigment.

17. A process for validating a batch of a pharmaceutical product
containing
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide or a salt thereof and a pharmaceutically acceptable carrier
for distribution comprisinga) subjecting a sample of the batch to
stability testing;b) determining the total amount of an oxidation
decomposition product in the sample of the batch after stability testing;
andc) validating the batch for distribution only if the sample of the
batch after stability testing contains not more than a total of 0.5% w/w
relative to
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide of the oxidation decomposition products of
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide.

18. The process of claim 17, wherein the oxidation decomposition product
is 2-Chloro-6-(1-ethyl-N-methyl-2-oxoindoline-3-carboxamido)benzoic
acid,5-Chloro-N-ethyl-3-hydroxy-1-methyl-2,4-dioxo-N-phenyl-1,2,3,4-tetra-
hydro-quinoline-3-carboxamide or
1H,3H-spiro[5-chloro-1-methylquinoline-2,4-dione-3,3'-[1]ethylindolin-[2]-
-one], or a mixture thereof.

19. The process of claim 17, wherein in the step (b), the amount is
determined using a measurement of mass, ultraviolet absorption,
refractive index, ionization or voltammogram.

20-22. (canceled)

23. A process for preparing a pharmaceutical product comprising
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide or a salt thereof and a pharmaceutically acceptable carrier,
wherein the pharmaceutical product has not more than a total of 0.5% w/w
relative to
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide of the oxidation decomposition products
2-Chloro-6-(1-ethyl-N-methyl-2-oxoindoline-3-carboxamido)benzoic
acid,1H,3H-spiro[5-chloro-1-methylquinoline-2,4-dione-3,3'-[1]ethylindoli-
n-[2]-one], and
5-Chloro-N-ethyl-3-hydroxy-1-methyl-2,4-dioxo-N-phenyl-1,2,3,4-tetrahydro-
-quinoline-3-carboxamide, comprisinga) obtaining a batch of
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide or a salt thereof;b) determining the total amount of
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide or a salt thereof present in the batch; andc) preparing the
pharmaceutical product from the batch only if the batch is determined to
have not more than a total of 0.5% w/w relative to
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide of the oxidation decomposition products
2-Chloro-6-(1-ethyl-N-methyl-2-oxoindoline-3-carboxamido)benzoic
acid,1H,3H-spiro[5-chloro-1-methylquinoline-2,4-dione-3,3'-[1]ethylindoli-
n-[2]-one], and
5-Chloro-N-ethyl-3-hydroxy-1-methyl-2,4-dioxo-N-phenyl-1,2,3,4-tetrahydro-
-quinoline-3-carboxamide.

24. A process for testing whether a sample contains an undesirable
oxidation decomposition products of
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide which comprises determining whether the sample contains a
compound having the structure: ##STR00012##

25. An isolated compound having the structure: ##STR00013##

26. (canceled)

Description:

[0001]This application claims the benefit of U.S. Provisional Application
No. 61/008,698, filed Dec. 20, 2007, the entire content of which is
hereby incorporated by reference herein.

[0002]Throughout this application various publications, published patent
applications, and patents are referenced. The disclosures of these
documents in their entireties are hereby incorporated by reference into
this application in order to more fully describe the state of the art to
which this invention pertains.

BACKGROUND OF THE INVENTION

[0003]Laquinimod is a compound which has been shown to be effective in the
acute experimental autoimmune encephalomyelitis (aEAE) model (U.S. Pat.
No. 6,077,851). Its chemical name is
N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-
-carboxamide, and its Chemical Registry number is 248281-84-7. The
processes of synthesis of laquinimod and the preparation of its sodium
salt are disclosed in U.S. Pat. No. 6,077,851. An additional process of
synthesis of laquinimod is disclosed in U.S. Pat. No. 6,875,869.

[0006]The subject invention also provides a sealed package comprising the
pharmaceutical composition described herein or a pharmaceutically
acceptable salt thereof and an oxygen absorbing agent.

[0007]The subject invention also provides a process for the manufacture of
a sealed package comprising a pharmaceutical composition of
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide or a pharmaceutically acceptable salt thereof comprising
preparing a pharmaceutical composition comprising a pharmaceutical
composition of
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide or a pharmaceutically acceptable salt thereof and packaging
said pharmaceutical composition in a container under environmental
conditions containing less oxygen than standard atmospheric conditions.

[0008]The subject invention also provides a pharmaceutical formulation in
tablet form wherein the tablet comprises a core comprising
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide or a pharmaceutically acceptable salt thereof and a
pharmaceutically acceptable carrier and a coating which inhibits oxygen
from contacting the core.

[0009]The subject invention also provides a process for validating a batch
of a pharmaceutical product containing
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide or a salt thereof and a pharmaceutically acceptable carrier
for distribution.

[0010]The subject invention also provides a process for validating a batch
of N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoli-
ne-3-carboxamide or a salt thereof for distribution.

[0011]The subject invention also provides a process for preparing a
pharmaceutical product comprising
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide or a salt thereof and a pharmaceutically acceptable carrier,
wherein the pharmaceutical product has not more than a total of 0.5% w/w
relative to
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide of the oxidation decomposition products
2-Chloro-6-(1-ethyl-N-methyl-2-oxoindoline-3-carboxamido)benzoic
acid,1H,3H-spiro[5-chloro-1-methylquinoline-2,4-dione-3,3'-[1]ethylindoli-
n-[2]-one], and
5-Chloro-N-ethyl-3-hydroxy-1-methyl-2,4-dioxo-N-phenyl-1,2,3,4-tetrahydro-
-quinoline-3-carboxamide.

[0016]In an embodiment of the pharmaceutical composition the
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide is in the form of a pharmaceutically acceptable salt.

[0017]In another embodiment of the pharmaceutical composition, the
pharmaceutically acceptable salt of
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide is a lithium salt, a sodium salt or a calcium salt.

[0018]In another embodiment of the pharmaceutical composition, the
pharmaceutically acceptable salt of
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide is
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide sodium.

[0019]In an embodiment, the pharmaceutical composition is in solid form.

[0020]In another embodiment, the pharmaceutical composition is
characterized in that 1.0% or less of the of
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide or of the pharmaceutically acceptable salt thereof degrades
upon exposure to a 0.15% H2O2 solution for 40 minutes.

[0021]In yet another embodiment, the pharmaceutical composition is free of
oxidation decomposition products of
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide.

[0023]In yet another embodiment, the pharmaceutical composition contains
less than 1% by weight of oxidation decomposition products of
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide.

[0024]In yet another embodiment, the pharmaceutical composition is free of
2-Chloro-6-(1-ethyl-N-methyl-2-oxoindoline-3-carboxamido)benzoic
acid,1H,3H-spiro[5-chloro-1-methylquinoline-2,4-dione-3,3'-[1]ethylindoli-
n-[2]-one], and
5-Chloro-N-ethyl-3-hydroxy-1-methyl-2,4-dioxo-N-phenyl-1,2,3,4-tetrahydro-
-quinoline-3-carboxamide.

[0025]In yet another embodiment, the pharmaceutical composition contains
not more than 0.5% w/w relative to
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide of
2-Chloro-6-(1-ethyl-N-methyl-2-oxoindoline-3-carboxamido)benzoic
acid,1H,3H-spiro[5-chloro-1-methylquinoline-2,4-dione-3,3'-[1]ethylindoli-
n-[2]-one], or
5-Chloro-N-ethyl-3-hydroxy-1-methyl-2,4-dioxo-N-phenyl-1,2,3,4-tetrahydro-
-quinoline-3-carboxamide.

[0026]The subject invention also provides a sealed package comprising the
pharmaceutical composition described herein or a pharmaceutically
acceptable salt thereof and an oxygen absorbing agent.

[0027]In an embodiment of the sealed package, the oxygen absorbing agent
is iron.

[0028]The subject invention also provides a process for the manufacture of
a sealed package comprising a pharmaceutical composition of
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide or a pharmaceutically acceptable salt thereof comprising
preparing a pharmaceutical composition comprising a pharmaceutical
composition of
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide or a pharmaceutically acceptable salt thereof and packaging
said pharmaceutical composition in a container under environmental
conditions containing less oxygen than standard atmospheric conditions.

[0029]The subject invention also provides a pharmaceutical formulation in
tablet form wherein the tablet comprises a core comprising
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide or a pharmaceutically acceptable salt thereof and a
pharmaceutically acceptable carrier and a coating which inhibits oxygen
from contacting the core.

[0030]In one embodiment, the coating comprises a cellulosic polymer, a
detackifier, a gloss enhancer, and pigment. A detackifier is a substance
added to a screen printing ink as a means of reducing its stickiness, or
tack, and improve the ink's flow characteristics. Examples of
detackifiers are lecithins, stearic acid, polysorbates, glyceryl
monostearate, sodium lauryl sulfate, poloxamers, monoglycerides,
diglycerides and mixtures thereof. In an embodiment, the coating is
Opadry®fx®, manufactured by Colorcon, West Point, Pa., USA.
Opadry®fx® is described in U.S. Pat. No. 6,902,609, the entire
content of which is hereby incorporated by reference herein.

[0031]Opadry®fx® is a pearlescent film coating system which has
been found to have excellent oxygen barrier properties compared to other
tablet film coating systems. In one study, Opadry®fx® was found to
inhibit oxidation of ibuprofen at various temperatures by acting as an
oxygen barrier. The oxidation rate of ibuprofen coated with
Opadry®fx® was found to be very slow and difficult to quantify
even at high temperatures (60° C.). (Gulian et al., "Oxidative
Protection of Ibuprofen Using Opadry®fx® Special Effects Film
Coating System" American Academy of Pharmaceutical Scientists, November,
2004).

[0032]In addition, Opadry®fx® was found to provide oxidative
protection from stressed illumination conditions. Gulian et al. compared
degradation product profiles for uncoated ibuprofen tablets, tablets
coated with hydroxypropylmethylcellulose (HPMC)/TiO2 and tablets
coated with Opadry®fx® in stressed UV and visible light
conditions. The results showed that tablets coated with Opadry®fx®
have the lowest amount of degradants. This study strongly suggests that
the primary photolytic degradation pathways are oxidative in nature.
Since oxygen is an essential co-reactant during these photolytic
degradation processes, the low oxygen permeability of Opadry®fx®
results in lower levels of degradants. (Gulian et al.)

[0034]The subject invention also provides a process for validating a batch
of a pharmaceutical product containing
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide or a salt thereof and a pharmaceutically acceptable carrier
for distribution comprising [0035]a) subjecting a sample of the batch
to stability testing; [0036]b) determining the total amount of an
oxidation decomposition product in the sample of the batch after
stability testing; and [0037]c) validating the batch for distribution
only if the sample of the batch after stability testing contains not more
than a total of 0.5% w/w relative to
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide of the oxidation decomposition products
2-Chloro-6-(1-ethyl-N-methyl-2-oxoindoline-3-carboxamido)benzoic
acid,1H,3H-spiro[5-chloro-1-methylquinoline-2,4-dione-3,3'-[1]ethylindoli-
n-[2]-one], and
5-Chloro-N-ethyl-3-hydroxy-1-methyl-2,4-dioxo-N-phenyl-1,2,3,4-tetrahydro-
-quinoline-3-carboxamide.

[0038]In an embodiment of the process, wherein the oxidation decomposition
product is
2-Chloro-6-(1-ethyl-N-methyl-2-oxoindoline-3-carboxamido)benzoic
acid,5-Chloro-N-ethyl-3-hydroxy-1-methyl-2,4-dioxo-N-phenyl-1,2,3,4-tetra-
hydro-quinoline-3-carboxamide or
1H,3H-spiro[5-chloro-1-methylquinoline-2,4-dione-3,3'-[1]ethylindolin-[2]-
-one], or a mixture thereof.

[0039]In another embodiment of the process, wherein in the step (b), the
amount is determined using a measurement of mass, ultraviolet absorption,
refractive index, ionization or voltammogram.

[0040]The subject invention also provides a process for validating a batch
of N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoli-
ne-3-carboxamide or a salt thereof for distribution comprising [0041]a)
subjecting a sample of the batch to stability testing; [0042]b)
determining the total amount of an oxidation decomposition product in the
sample of the batch after stability testing; and [0043]c) validating the
batch for distribution only if the sample of the batch after stability
testing contains not more than a total of 0.1% w/w relative to
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide of the oxidation decomposition products
2-Chloro-6-(1-ethyl-N-methyl-2-oxoindoline-3-carboxamido)benzoic
acid,1H,3H-spiro[5-chloro-1-methylquinoline-2,4-dione-3,3'-[1]ethylindoli-
n-[2]-one], and
5-Chloro-N-ethyl-3-hydroxy-1-methyl-2,4-dioxo-N-phenyl-1,2,3,4-tetrahydro-
-quinoline-3-carboxamide.

[0044]In an embodiment of the process, wherein the oxidation decomposition
product is
2-Chloro-6-(1-ethyl-N-methyl-2-oxoindoline-3-carboxamido)benzoic
acid,5-Chloro-N-ethyl-3-hydroxy-1-methyl-2,4-dioxo-N-phenyl-1,2,3,4-tetra-
hydro-quinoline-3-carboxamide or
1H,3H-spiro[5-chloro-1-methylquinoline-2,4-dione-3,3'-[1]ethylindolin-[2--
one], or a mixture thereof.

[0045]In another embodiment of the process, wherein in the step (b), the
amount is determined using a measurement of mass, ultraviolet absorption,
refractive index, ionization or voltammogram.

[0046]The subject invention also provides a process for preparing a
pharmaceutical product comprising
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide or a salt thereof and a pharmaceutically acceptable carrier,
wherein the pharmaceutical product has not more than a total of 0.5% w/w
relative to
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide of the oxidation decomposition products
2-Chloro-6-(1-ethyl-N-methyl-2-oxoindoline-3-carboxamido)benzoic
acid,1H,3H-spiro[5-chloro-1-methylquinoline-2,4-dione-3,3'-[1]ethylindoli-
n-[2]-one], and
5-Chloro-N-ethyl-3-hydroxy-1-methyl-2,4-dioxo-N-phenyl-1,2,3,4-tetrahydro-
-quinoline-3-carboxamide, comprising [0047]a) obtaining a batch of
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide or a salt thereof; [0048]b) determining the total amount of
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide or a salt thereof present in the batch; and [0049]c)
preparing the pharmaceutical product from the batch only if the batch is
determined to have not more than a total of 0.5% w/w relative to
N-ethyl-N-phenyl-1,2,-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline--
3-carboxamide of the oxidation decomposition products
2-Chloro-6-(1-ethyl-N-methyl-2-oxoindoline-3-carboxamido)benzoic
acid,1H,3H-spiro[5-chloro-1-methylquinoline-2,4-dione-3,3'-[1]ethylindoli-
n-[2]-one], and
5-Chloro-N-ethyl-3-hydroxy-1-methyl-2,4-dioxo-N-phenyl-1,2,3,4-tetrahydro-
-quinoline-3-carboxamide.

[0050]The subject invention also provides a process for testing whether a
sample contains an undesirable oxidation decomposition products of
2-Chloro-6-(1-ethyl-N-methyl-2-oxoindoline-3-carboxamido)benzoic
acid,1H,3H-spiro[5-chloro-1-methylquinoline-2,4-dione-3,3'-[1]ethylindoli-
n-[2]-one], or
5-Chloro-N-ethyl-3-hydroxy-1-methyl-2,4-dioxo-N-phenyl-1,2,3,4-tetrahydro-
-quinoline-3-carboxamide which comprises determining whether the sample
contains a compound having the structure:

##STR00003##

[0051]The subject invention also provides an isolated compound having the
structure:

##STR00004##

[0052]The subject invention also provides an isolated compound having the
structure:

##STR00005##

[0053]Every embodiment of the invention is contemplated as being employed
with every other disclosed embodiment. For example, the pharmaceutical
composition disclosed can be packaged in the sealed package disclosed,
and such combination can be manufactured by the disclosed processes and
methods.

[0054]Many of the prior art formulations of Laquinimod relate to
formulations comprising alkaline agents and meglumine. Both of these
excipients have been found to be incompatible with certain coloring
agents in capsules, as capsule spotting was detected in various capsules.
This was attributed to the alkalinity of the formulation. An advantage of
the formulations provided herein is the stability and compatibility with
many types of colors.

[0055]As used herein, "oxidation reducing agent" refers to a group of
chemicals which includes an "antioxidant", a "reduction agent" and a
"chelating agent".

[0057]The term "antioxidant" as used herein also refers to Flavonoids such
as those selected from the group of quercetin, morin, naringenin and
hesperetin, taxifolin, afzelin, quercitrin, myricitrin, genistein,
apigenin and biochanin A, flavone, flavopiridol, isoflavonoids such as
the soy isoflavonoid, genistein, catechins such as the tea catechin
epigallocatechin gallate, flavonol, epicatechin, hesperetin, chrysin,
diosmin, hesperidin, luteolin, and rutin.

[0063]The capsules were made using the following steps: [0064]1.
Mannitol and 99% of the total desired anhydrous sodium carbonate were
placed into a high shear granulating mixer and were mixed for 30 seconds.
[0065]2. A solution of laquinimod sodium, 1% of the total desired
anhydrous sodium carbonate and purified water was prepared in a mixer
until dissolved. [0066]3. The solution from step 2 was added to the
contents of the high shear granulating mixer of step 1 and was mixed to
form a suitable granulate. [0067]4. The granulate was dried in a fluid
bed dryer with the inlet air temperature of 50° C. and outlet air
temperature of 40° C. [0068]5. The dry granulate was milled using
a 0.8 mm screen, and blended with sodium stearyl fumarate. [0069]6. The
mixture from step 5 was filled into size 1 hard gelatin capsules (0.5 mL
volume) for the 0.6 mg laquinimod acid dose and into size 3 hard gelatin
capsules (0.3 mL volume) for the 0.3 mg of laquinimod acid dose.

Example 2a

Laquinimod Sodium Capsules Comprising Meglumine

[0070]Capsules were made which corresponded to 0.3 mg of laquinimod acid
(LA) per capsule and 0.6 mg of laquinimod acid per capsule using the
following excipients as shown in Table 2:

[0071]The capsules were made using the following steps: [0072]1.
Mannitol and 90% of the total desired meglumine were placed into a high
shear granulating mixer and were mixed for 30 seconds. [0073]2. A
solution of laquinimod sodium, 10% of the total desired meglumine and
purified water was prepared in a mixer until dissolved. [0074]3. The
solution from step 2 was added to the contents of the high shear
granulating mixer of step 1 and mixed to form a suitable granulate.
[0075]4. The granulate was dried in a fluid bed dryer with the inlet air
temperature of 50° C. and outlet air temperature of 40° C.
[0076]5. The dry granulate was milled using a 0.8 mm screen, and blended
with sodium stearyl fumarate. [0077]6. The mixture from step 5 was filled
into size 1 hard gelatin capsules (0.5 mL volume) for the 0.6 mg
laquinimod acid dose and into size 3 hard gelatin capsules (0.3 mL
volume) for the 0.3 mg of laquinimod acid dose.

Example 2b

Laquinimod Sodium Tablets Comprising Meglumine

[0078]Laquinimod sodium tablets were prepared using the same excipients as
in table 2 and using the same procedure as in steps 1-5 of example 2a.
After step 5, the blend was transferred into a tabletation machine and
punched. The tablets were tested for average weight, individual weight,
thickness, hardness, friability and disintegration.

Example 3

Forced Degradation of Laquinimod Sodium Capsules

[0079]Laquinimod sodium capsules manufactured according to Examples 1 and
2 were exposed to 0.15% H2O2 solution for 40 minutes.

[0080]The amount of sodium laquinimod in each capsule after exposure was
measured using a chromatographic assay, and the percent decrease is
listed below:

[0081]Formulation of Example 1: 28.5% decrease.

[0082]Formulation of Example 2: 0.7% decrease.

Results

[0083]The use of meglumine as an excipient in sodium laquinimod prevented
oxidation-related degradation of laquinimod sodium under forced
conditions.

[0084]Laquinimod Sodium formulations are prepared using the process
described in Example 2 with the use of antioxidants in the place of
meglumine, or in addition to meglumine in the following proportions:

[0085]An oxygen absorbing agent is a material that removes oxygen from a
closed container by reacting with it chemically to bind it.

[0086]A preferred example of an oxygen absorbing agent is iron, preferably
in powdered form. In a sealed container, the oxygen absorbing agent
maintains the oxygen content of the air in the headspace of the container
at a level preferably lower than 10%, and most preferably, lower than 1%.

[0087]Other metals which can be used include nickel, tin, copper and zinc.

[0088]Examples of oxygen absorbers have been disclosed in US Application
Publication Number US 2007/0163917.

[0089]Laquinimod sodium formulations are packaged in closed containers
containing oxygen absorber and in closed containers without oxygen
absorbers. After a month, the amount of laquinimod is determined in the
formulations in both containers.

[0090]Oxygen absorbers can be useful in lowering the amount of
oxygen-based degradation in the laquinimod formulations.

[0091]Laquinimod Sodium Formulations are packaged in containers sealed in
an oxygen-free or in a reduced-oxygen environment. The formulations are
stored for a month. The content of laquinimod in the formulations is
compared to similar formulations which are packaged in standard
non-oxygen-reduced environments.

[0092]Oxygen absorbers can be useful in lowering the amount of
oxygen-based degradation in the laquinimod formulations.

Example 7

Coating of Laquinimod Tablets with an Oxygen-Proof Coating

[0093]Tablets are coated with a film coating which prevents contact of the
atmosphere. The film does not significantly change the dissolution
profile of the tablet, yet prevents contact of oxygen in the air within
the packaging with the laquinimod in the tablet.

[0094]The coating may be a wax or a coating such as Opadry®fx®
manufactured by Colorcon, West Point, Pa., USA.

[0095]Coatings may be used on laquinimod tablets with meglumine, without
meglumine, with antioxidants or without antioxidants.

[0096]Oxygen-proof coatings can be useful in lowering the amount of
oxygen-based degradation in the laquinimod formulations.

[0098]These oxidation products may be formed in the presence of laquinimod
and oxygen. Factors which may increase the formation of these products
include water and/or transition metal ions, which are in direct contact
with the laquinimod, e.g. which are in the formulation.

Discussion

[0099]The use of meglumine reduces the degradation of the laquinimod
sodium in a formulation. Specifically, when exposed to 0.15%
H2O2 solution for 40 minutes the formulation with meglumine of
Example 2 exhibited less than 2.5% of laquinimod sodium degradation as
compared to an analogous formulation without meglumine under the same
conditions. Meglumine appears to be acting to reduce the oxidation of
laquinimod. Therefore, other methods for preventing or reducing
oxidation, such as the methods described herein, may be used to reduce
the oxidation of laquinimod and prevent or inhibit formation of oxidation
degradation products. Such methods include formulating laquinimod with
antioxidant, chelating agent, and/or reduction agent, as well as
packaging methods, coating methods and/or processing methods designed to
reduce oxidation.

[0100]To determine whether any given method for preventing or reducing
oxidation is effective, known techniques may be employed to identify
whether a laquinimod composition contains any one of Compound I, II, or
III, or mixtures thereof.

Example 9

Preparation of Compound II

##STR00009##

[0102]Laquinimod (14.01 mmol, 5.00 g), CAN (28.02 mmol, 15.4 g), ethanol
(99.5%, 50 ml), and acetic acid (5.0 ml) were stirred at ambient
temperature for 1 hour and water (30 ml) was then added. After stirring
for 10 min the precipitate was collected by filtration, washed with
water, then washed with cold ethanol (99.5%), and dried to yield the
spiro Compound II (4.73 g, 95%).

Example 10

Preparation of Compound I

##STR00010##

[0104]The Compound II from Example 9 (5.15 mmol, 1.83 g) was stirred in a
mixture of 1M NaOH (10.0 mmol, 10.0 mL) and 1,4-dioxane (4 mL) at room
temperature for 2 h and then diluted with water (30 mL). The mixture was
acidified with 5 M HCl to pH 1, stirred for 15 min and the precipitate
was collected, washed with water and dried to afford Compound I (1.73 g,
90% yield). When Compound I is heated in ethanol the molecule decomposes
into 2-methylamino-6-chloro benzoic acid and
1-ethyl-2-oxo-2,3-dihydro-1H-indole-3-carboxylic acid ethyl ester.
Compound I is purified by dissolution in a mixture of ethanol and aqueous
1 M NaOH and precipitation at room temperature by addition of HCl.

[0107]Two wet granulations were prepared from Laquinimod Na, mannitol,
lactose and water (Batches 1 and 2). One batch (Batch 1) did not contain
antioxidants Butylated hydroxytoluene (BHT) and Butylated hydroxyanisole
(BHA). For the other batch (Batch 2), the antioxidants (BHT and BHA) were
dissolved in EtOH and added to the granulate.

[0108]The granulates were dried and milled. For both batches, 10% of
Crospovidone was added and mixed for 15 minutes and then Pruv® was
added and mixed for 5 minutes. The final blends were tested for non-Polar
IDD (3-HLAQ) (Compound III). The compositions of batches 1 and 2 and the
resulting percent 3-HLAQ (Compound III) impurity relative to Laquinimod
are shown in Table 5. The impurities were detected before storage at
accelerated conditions.

[0110]In one batch (Batch 3), the granulate was dried and milled. Then
0.1% Pruv® was added and mixed for 5 minutes. The final blend was
tested for non-Polar IDD (3-HLAQ) (Compound III).

[0111]In the other batch (Batch 4), antioxidants (BHT, BHA and Propyl
Gallate) were dissolved in EtOH and added to granulate. The granulate was
dried and milled. The blend was tested for non-Polar IDD (3-HLAQ)
(Compound III). The impurities were detected before storage at
accelerated conditions.

[0112]The compositions of each batch and resulting percent 3-HLAQ
(Compound III) impurity relative to Laquinimod are shown in Table 6.